variations in reference values utilized in pulmonary function tests

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Süleyman Savaş Hacıevliyagil, Levent Cem Mutlu, Gazi Gülbaş, Özkan Yetkin, Hakan Günen

Inonu University Faculty of Medicine Department of Pulmonary Medicine

Malatya, TURKEY

VARIATIONS IN REFERENCE VALUES UTILIZED IN

PULMONARY FUNCTION TESTS

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Introduction

Pulmonary function tests (PFT) are used to evaluate and stage the abnormalities in the functions of the respiratory system.

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Introduction

• Results of PFT measurements are defined according to the comparisons made with the reference values obtained by using sex, height and age parameters in healthy individuals.

• In our country, usually, Knudson’s reference values are used in PFT measurements.

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Aim

The aim of this study is to investigate whether these reference values are suitable for our region or not.

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Material and Methods

311 non-smoker individuals living in Malatya, over 18, without any respiratory symptom or respiratory disease in the past were included in the study using stratified cluster sampling method.

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Material and Methods

• All subjects performed forced vital capacity maneuver, and their PFTs were measured at least for three times.

• FVC, FEV1, FEV1/FVC, FEF25-75 and PEF parameters were used in our evaluations.

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Material and Methods

For these parameters, new formulations deriving from regression curves were obtained using independent parameters age and height, separately for both sexes.

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Material and Methods

The best PFT measurements were compared with the Knudson’s reference values using student-t test.

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Results

• 311 participants

• 189 males, 122 females

• Age: 45.6±17.2 years

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Constant Height Age r2 p SEE

Females

FVC -1.685 -0.00352 -0.00210 0.728 0.000 0.31108

FEV1 -0.876 0.00267 -0.00181 0.685 0.000 0.28238

FEV1/FVC 245.922 -841 -441 0.010 0.562 72.27523

FEF%25-75 0.648 0.002128 -0.0303 0.237 0.487 0.73952

PEF -6.011 0.007029 -0.00147 0.323 0.000 0.80909

Males

FVC -5.065 -0.00619 -0.00273 0.743 0.000 0.48926

FEV1 -3.160 0.0047 -0.00287 0.781 0.000 0.40290

FEV1/FVC 114.609 -141 -122 0.37 0.031 9.81641

FEF%25-75 -0.329 0.00277 -0.00349 0.282 0.000 0.94770

PEF -0.347 0.00530 -0.00411 0.124 0.100 2.10799

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Current study Values according to Knudsons’

reference values

Differences p

Females

FVC 2.96±0.53 2.87±0.59 0.089±0.31 0.002

FEV1 2.52±0.49 2.48±0.50 0.0307±0.27 0.211

FEV1/FVC 83.67±3.50 95.79±81.1 -12.13±80.8 0.145

FEF%25-75 2.96±0.45 2.61±0.82 0.34±0.79 0.006

PEF 5.83±0.64 4.23±0.96 1.59±0.77 0.000

Males

FVC 4.09±0.92 4.14±0.95 -0.042±0.49 0.235

FEV1 3.37±0.82 3.46±0.85 -0.096±0.39 0.001

FEV1/FVC 81.4±3.03 83.9±8.45 -2.51±7.69 0.000

FEF%25-75 3.73±0.70 3.28±1.1 0.45±0.97 0.000

PEF 8.27±0.84 6.59±2.22 1.68±2.1 0.000

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Tartışma

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Conclusions

• In conclusion, we have found some variations between the Knudson’s reference values and our PFT values obtained from healthy individuals in our region.

• We think that the definition of accurate reference values in our country may enable the clinicians better evaluate the patients.

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Goal

To achieve this goal, it is necessary to perform multicentric studies.